Cellulosed molded article having a functional effect and method for producing the same

ABSTRACT

The invention relates to a method for producing cellulosed molded articles having a functional effect. The method is characterized by charging cellulosed fibers or films with incorporated ion exchangers having bactericidal metal ions and/or ionic pharmaceutical active substances in such a manner that a depot of these active substances is built up in the fiber. Said depot time releases the active substances in the amount of the corresponding equivalent concentration when the fibers and films are used in aqueous solutions. The invention also relates to molded articles produced according to the inventive method.

The invention relates to cellulosic forms as well as a method forproducing cellulosic forms by the dry-wet extrusion process withimproved and enhanced functional effects, especially applicable inmedicine, hygiene, garment, paper manufacturing and packaging industry.

The functional effect is directed to a steady and meticulouslyadjustable bactericide effect, especially for wound contact material,sports and leisure clothing, hospital textiles, filter and packagingpapers.

PRIOR ART

It is well known that heavy metal ions like e.g. silver,quicksilver/mercury, copper, zinc and zirconium ions are deadening orgrowth inhibiting to bacteria, viruses, fungi or spores (Thurman et al.,CRC Crit. Rev. In Environ. Contr. 18 (4), P. 295-315 (1989)). Withrespect to the bactericide effect silver ions are of particularinterest. The important advantage of silver ions against otherbactericide metal ions, like e.g. Hg²⁺, is the insensibility of thehuman metabolism against silver. The bactericide acting concentration isdenoted for silver as 0.01-1 mg/l (Ullman's Encyclopedia of IndustrialChemistry (5. Edition), VCH 1993, Volume A 24, P. 160).

This effect of silver ions is used in different applications. In themanufacture of textile fibres silver is for example galvanicallydeposited on the surface of polyamide silk. Working up of saidgalvanically silver-plated polyamide silk on knitters and moulders isproblematical, since the silver layer of the polyamide silk is partiallydeposited on the yarn leading devices leading to numerous shut downs ofsaid devices. It is further known to introduce metallic silver,silver-zeolite or silver-glass ceramics into the matrix of the fibre ofmelt spun fibres like polypropylene fibres, polyester fibres andpolyamide fibres (Taschenbuch für die Textilindustrie 2003, Schiele &Schön Berlin, P. 124 ff).

The use of silver-zeolite and silver-glass ceramics was also proposedfor acrylic fibres. Also cellulosic fibres with bacteriostatic andbactericidal properties are available on the market. Incorporation oftriclosan (2,4,4-trichloro(II)-hydroxyphenyleneether) into cellulosicfibres leads to a permanently bacteriostatic fibre (ITB InternationalTextile Bulletin 3/2002). Said substance is active against bacteriausually occurring on skin, including pathogenic staphylococcus-types.

DE 10 140 772 discloses a method for producing cellulosic forms withincorporated algae. Said forms are able to adsorb metals from heavymetal containing media. The heavy metal loaded forms may be used asantibacterial and/or fungicidal material. The content of adsorbed heavymetals in said cellulosic forms is given as at least about 70 mg/kg,related to the total weight of the cellulosic forms.

It is further disclosed that by dipping a fibre with a content of brownalgae of 11.39 weight-%, based on the weight of the fibre, into a 0.05 MAgNO₃-solution a silver content of 1855 mg/kg per fibre was obtained.Since algae are natural products the capacity for binding said heavymetals varies. During binding of heavy metals onto algae differentbinding mechanisms are relevant, like ion exchange, complexing andfurther unknown reactions. The binding of said heavy metals onto saidalgae is therefore non-specific. A further disadvantage of said fibre isthat only cations may be used for a bactericidal effect, but nobactericidal anions, e.g. benzoic acid and sorbic acid.

WO 00/63470 relates to a method for the production of cellulosic formswith a high adsorption ability, wherein usual ion exchange particleswith grain size of >=25 μm are added to said forms prepared by theLyocell method. Furthermore, the adsorption of heavy metal ions isdisclosed, namely of copper and lead, with a capacity of 0.01 mmol/g,using an anion exchanger of a styrene-divinyl benzene copolymer.

Patent Abstracts of Japan, Edition 0152, No. 01 (C-0834) of JP 3 054234discloses the production of a cellulosic composition comprising an ionexchanger functionality, useful as binder for metal ions, wherein saidproduction process consists of mixing a specifically generated celluloseand an anionic polymer followed by solidification of said mixture.

AIM OF THE INVENTION

Aim of the present invention is to provide a cellulosic form withfunctional effect as well as a method for preparing said cellulosicform, especially for the use in medicine, hygiene and garment, whereinsaid forms have a bactericide effect and wherein especially saidadvantages go along with breathable clothing. A further aim is to keepsaid active agents in a textile depot and further to obtain sufficientrelease of said agents from said depot over a period of time. Thereleased concentrations of said agent should be controllable. Furtherthe forms, especially fibres or foils, obtainable by the method of theinvention, should be formed thus, that they are useful for preparingwound overlays, band-aids, sanitary products, textiles, special papersand packaging material, because of the high adsorption ability of activeagents. Finally composites including differing fibres should beproducible.

Further advantages are shown in the following description.

The aim is reached in combination with the aforementioned discussedmethod according to the present invention by charging the cellulosicforms, wherein said forms are spun according to the dry-wet extrusionmethod and having incorporated weakly linked cationic active ionexchangers with active agents. Surprisingly it was found that thebinding capacity for said active agents depends on the degree ofcross-linking of the ion exchanger. Thus, the binding capacity for thecationic active agents, like e.g. silver could be increased by more thanthe double amount, if polyacrylates are used, which were weaklycross-linked by a multifunctional cross-linker.

Weakly cross-linked ion exchangers according to the present inventionare ion exchangers with a decreased amount of cross-linkers. Usual ionexchanger resins show an amount of cross-linkers of 4 to 12 weight-%,based on the weight of the ion exchanger resin. Weakly cross-linked ionexchangers according to the present invention have an amount ofcross-linkers ranging from 0.1 to 2.0 weight-%, preferably 0.3 to 1.5weight-%, particularly preferably 0.5 to 1.2 weight-%.

Weakly cross-linked ion exchanger resins are characterized by thepronounced ability to swell considerably in aqueous solutions. Usual ionexchange resins with the aforementioned amount of cross-linkers showonly a minor degree of swelling.

Fibres made with incorporated weakly cross-linked cation exchangers showa capacity for binding silver ions which surpasses the capacity offibres with brown algae according to DE 10 140 772 up to the 28-fold.Thus, the opportunity is given to produce fibres or foils which may beheavily loaded with cationic active bactericide agents like silver ions.A fibre with 15 weight-% incorporated weakly cross-linked cationic ionexchanger may be loaded with about 80 g silver. Silver loads of fibresof >100 g Ag/kg fibre are possible, if the amount of the incorporatedweakly cross-linked cation exchanger is increased accordingly.

Said fibres may be mixed with other fibres, e.g. cotton, wool orsynthetic fibres, to produce yarns with the desired silver content. Thisprocedure allows the production of bactericidic yarns in a very economicway.

However, incorporation of ion exchangers leads with an increasing amountwithin the fibre to a disadvantageous influence on the textile physicalparameters like strength, elongation and loop strength. In particularstrength and loop strength will be reduced with an increasing amount ofincorporated ion exchanger.

Thus, it is also of economic interest to provide silver loaded fibresshowing textile physical properties, like strength and loop strengthwhich come close to the properties of fibres which do not containincorporated ion exchangers.

With the present invention it is possible to obtain fibres with asufficient content of silver per fibre to show an adequate bactericideeffect, but no disadvantages in view of the textile physical parameters.According to the present invention it is possible with 0.5 to 1.5weight-%, based on the cellulose weight of the fibres, of incorporatedweakly cross-linked cation exchanger to bind 5000 to 10.000 mg Ag/kgfibre. Such fibres have a sufficient bactericide effect in the knownfield of use and are equal to non-modified fibres concerning theirtextile physical parameters. Processing of such fibres and yarns madethereof is possible on all kind of textile machinery.

If, instead of weakly cross-linked cation exchangers, ion exchangers areused on the basis of acrylic acid-divinylbenzene-copolymer-boundcarboxyl groups or on the basis of a styrene-divinylbenzene-copolymerbound chelat forming imino-diacetic-acid as described in DE 19 917 614,fibres are obtained, which are comparable in their bactericide effect.However, the capacity for silver ions is less than 50% of theaforementioned weakly cross-linked cation exchangers.

A measure for the bactericide effect of the fibres or yarns is theequilibration concentration of the active agent in aqueous solutionse.g. the concentration of the silver ions.

For this purpose fibres or yarns loaded with silver ions are put intodistilled water at a temperature of 20° C., followed by a measurement ofthe equilibration concentration of the silver ions after 24 h. Table 1shows the equilibration concentrations of silver ions and the load ofsilver in the fibres, while using weakly cross-linked cation exchangersor known ion exchangers cross-linked with divinyl-benzene. As shown theequilibration concentration of silver ions is on a level which is abovethe necessary concentration of 0.01 to 1 mg/l to obtain a bactericideeffect. The equilibration concentration may be controlled to eachdesired concentration level by mixing with other kinds of fibres. TABLE1 content of ion exchanger Ag-content of the fiberequilibration-concentration 7 weight % [g/kg] [mg/l Ag⁺] ion exchangerwith 13.5 2.9 —COOH-groups ion exchanger with 17.5 3.6 chelating groupsweakly linked cation 36.5 2.7 exchanger (inventive)

As shown in table 1, the fibres according to the present inventionprovide the equilibration concentration which is necessary to obtain anantimicrobial effect, at an increased Ag-content of the fibre at thesame time. The advantages thereof are obvious.

During the use of the fibres free Ag-ions are permanently released,whereby the equilibration concentration is uphold by the Ag deposited inthe fibre. Due to the improved storing properties of the inventivefibres the equilibration concentration may be uphold over an extendedperiod of time.

If weakly cross-linked cation exchangers and strongly basic anionexchangers, based on styrene-divinylbenzene-copolymer withtrialkylammonium-groups in chloride-form are incorporated into thefibre, said fibres may be loaded with cation-active and anion-activebactericide ions, like silver ions and benzoic acid or asorbic acid.

Thus, it is possible to use silver ions together with anion activeagents like e.g. benzoic acid and asorbic acid. Said substances aretoxicologically unobjectable as shown in several publications andtherefore they are qualified for a direct use in foods (Wallhäuβer,Sterilisation, Desinfektion, Konservierung, 4^(th) edition, time 1988,P. 396). Processing of such fibres in paper manufacturing or foils madethereof provide antimicrobial packages for food.

Further, the use of said functionalised fibres with cation active agentswithin medical applications is possible. Such fibres may bind agents,like nicotine. Said fibres may be manufactured into band-aids and usedfor transdermal, therapeutic systems.

Advantageously loading of said functional fibres may proceed by dippingthe fibres into a solution of appropriate ions. Said dipping may becarried out continuously or in batch mode. When dipping in continuousmode it is preferred to load the cut fibre in a separate bath duringsubsequent treatment.

The invention and its properties will be illustrated more clearly by thefollowing examples:

EXAMPLE 1

Powdery weakly cross-linked cation exchanger, based on a cross-linkedcopolymerisate of acrylic acid and sodium acrylate, having a grainsize<10 μm, is added to 12 weight-% cellulose solution inN-methylmorpholine-N-oxide monohydrate, in a weight proportion of 15weight-%, based on the cellulose proportion. This spinning solution washomogenised in a kneader and spun with a spinning nozzle with 480 holesand a spinning hole diameter of 80 μm at a temperature of about 90° C.The draw off speed was about 30 m/min. The multifile fibre was ledthrough several washing baths to wash out the residualN-methylmorpholine-N-oxides. The fibres were skidded and loaded in 10 Lof 0.1 M silver nitrate solution per kg fibre. After loading the fibreswere skidded and washed to remove residual silver nitrate. Finally thefibres are dried at a temperature of about 80° C. TABLE 2 yarn-countdtex 0.7 yarn-count related tensile tear resistance (dry) cN/tex 22.5elongation (dry) % 14.8 yarn-count-related tear resistance of interwovenloops cN/tex 7.5 Silver content g/kg fiber 80

Table 2 shows the parameters of the fibres as well as the silver contentper fibre. A highly loaded fibre offers the advantage, that by blendingthis fibre with other textile fibres, e. g. cotton, silver loaded yarnscan be economically obtained. For a content of roughly 5000 mg Ag/kgyarn the silver-fiber constitutes only a sixteenth of the yarn.

In contrast to the galvanised polyamide-fibres thus produced yarns showa good processability on knitting machines or moulders.

EXAMPLE 2

Fibres are produced according to example 1 with a titre of 0.17 tex anda content of weakly cross-linked cation exchanger of 6 weight-%, basedon the content of cellulose. These fibres are loaded with silveraccording to example 1. The fibre-parameters are given in table 3.

EXAMPLE 3

Fibres are made according to Example 1 with a titre of 0.5 tex and acontent of weakly cross-linked cation exchanger of 0.5 weight-%, basedon the cellulosic content. The loading with silver ions is carried outaccording to Example 1. The parameters of the fibres are shown in table3. Further, in table 3 a fibre without weakly cross-linked cationexchanger is shown for comparison. TABLE 3 fiber without weakly linkedcation example 2 example 3 exchanger yarn-count dtex 0.17 0.5 0.5yarn-count related cN/tex 35.8 37.6 38.1 tensile tear resistance (dry)elongation (dry) % 13.0 11.4 11.8 yarn-count-related tear cN/tex 8.2 9.19.5 resistance of loops silver content g/kg fiber 36.6 4.6 —

It is evident from examples 1 to 3, that the silver content on a fibreis adjustable over a wide range via the content of weakly cross-linkedcation exchanger. Even with 0.5 weight-% a high silver content isobtainable. The influence of 0.5 weight-% of the weakly cross-linkedcation exchanger on the textile parameters of the fibre is marginal.

EXAMPLE 4 (COMPARATIVE EXAMPLE)

To a cellulose slurry in 60% aqueous N-methylmorpholine-N-oxide anaqueous suspension of weakly acid macro-porous cation exchanger, basedon styrene-divinylbenzene-copolymer with chelating groups ofiminodiacetic acid, is added in such a concentration, that the spinnedfibres reach a content of 6 weight-%, based on the cellulosic content.After spinning said fibres are washed and loaded with silver ionsaccording to Example 1. Table 4 shows the parameters of the fibres.TABLE 4 example 4 example 5 yarn-count dtex 0.5 0.5 yarn-count relatedtensile tear cN/tex 31.2 30.9 resistance (dry) elongation (dry) % 14.213.5 yarn-count-related tear cN/tex 9.1 8.5 resistance of loops silvercontent g/kg fiber 17.5 13.6

EXAMPLE 5 (COMPARATIVE EXAMPLE)

Working corresponding to Example 4 and adding to the slurry 6 weight-%of a weakly acid macroporous cation exchanger, based on cross-linkedpolyacrylate in its sodium-form, so that the spun fibre contains 6weight-% ion exchanger based on the cellulose content, washing saidfibre and loading it with silver ions according to Example 1, oneobtains fibres with 13.6 g Ag/kg per fibre. Example 5 surprisingly showsthat the ion exchanger on the basis of polyacrylate binds about half theamount of silver ions compared to the weakly cross-linked cationexchanger based on polyacrylates. The rise of the binding capacity ofmore than 100% leads to technical and economical advantages in that onone hand small amounts of the weakly cross-linked cation exchanger inthe fibre barely influence the textile physical parameters, while on theother hand, based on the high incorporation of silver ions, aneconomical production by blending with other fibres is possible.

EXAMPLE 6

Fibres with weakly cross-linked cation exchangers as well as common ionexchangers of the prior art, made according to Examples 1 to 5 areloaded with silver, copper (II) and zinc ions. The results are shown inTable 5. TABLE 5 metal content g/kg fiber fiber incorporated with coppersilver silver/zinc 20 weight-% ion exchanger according to 23.7 57.123.9/27.5 example 4 (comparative example) 20 weight-% ion exchangeraccording to 11.5 41.7 36.4/24.5 example 5 (comparative example) 15weight-% weakly linked cation 25.5 85.5 59.3/30.5 exchanger as inexample 1 to 3

Fibres loaded with copper ions, silver ions or a combination of silverions and zinc ions may be used as bactericide fibres.

EXAMPLE 7

A suspension of weakly cross-linked cation exchanger based on across-linked copolymerisate of acrylic acid and sodium acrylate and astrong basic anion exchanger, based on astyrene-divinylbenzene-copolymer with trialkylammonium-groups inchloride form, in 85% N-methylmorpholine-N-oxide is added in such anamount to a 11 weight-% cellulose solution inN-methylmorpholine-N-oxide-monohydrate, such that the spinning solutioncontains 11 weight-% cellulose, based on the cellulose content, 8weight-% of the weakly cross-linked cation exchanger and 8 weight-% ofsaid anion exchanger. After homogenisation the spinning solution is spunaccording to Example 1 with a titre of 0.5 tex. The fibres show astrength of 26.3 cN/tex, an elongation of 12.1% and a yarn-count relatedtear-resistance of loops of 8.6 cN/tex.

The silver load is at 52.4 g silver/kg fibre and the load with benzoateat 16.6 g benzoate/kg fibre. These fibres possess a very strongbactericide effect. The example shows the appliccability of fibresaccording to the invention in combination with loaded fibres with anionexchangers and cation exchangers known from the prior art.

EXAMPLE 8

Ion-exchanging fibres or foils according to the invention withincorporated cation exchangers, produced corresponding to example 2, areloaded with nicotine. The loaded fibres or foils are washed and dried.These fibres or foils can be processed into textile depots and can beapplied as transdermal, therapeutic system.

EXAMPLE 9

The bactericide properties of fibres, produced according to example 1,were determined following the European Pharmacopaeia (EP 2002),‘Bioburden determination’.

Papers were examined, which contain fibres according to example 1 insuch an amount, that gradually altered silver contents in the paper of190 mg Ag/kg paper, 760 mg Ag/kg paper and 3800 mg Ag/kg paper resulted.The examination was carried out with the following micro-organisms(Tables 6-9):

Pseudomonas aeruginosa ATCC 9027

Staphylococcus aureus ATCC 6538

Bacillus subtilis spores ATCC 6633

Fusarium solani spores ATCC 36031. TABLE 6 Pseudomonas aeruginosamicrobial count after respective incubation time silver content 0minutes 1 day 3 days 7 days comparative 6.9 × 10₄ 7.8 × 10⁴ 5.9 × 10⁵4.5 × 10⁴ sample  190 mg Ag/kg 8.9 × 10⁴ 4.5 × 10³  77 <10  760 mg Ag/kg7.7 × 10⁴ 1.3 × 10³ <10 <10 3800 mg Ag/kg 8.7 × 10⁴ 3.3 × 10 <10 <10

TABLE 7 Staphylococcus aureus microbial count after respectiveincubation time silver content 0 minutes 1 day 3 days 7 days comparative1.1 × 10⁵ 1.2 × 10⁵ 1.4 × 10⁵ 9.6 × 10⁴ sample  190 mg Ag/kg 1.3 × 10⁵1.1 × 10⁵ 4.6 × 10³  36  760 mg Ag/kg 1.4 × 10⁵ 8.8 × 10⁴ 4.8 × 10³ <103800 mg Ag/kg 1.2 × 10⁵ 4.9 × 10⁴ 1.1 × 10³ <10

TABLE 8 Fusarium solani spores microbial count after respectiveincubation time silver content 0 minutes 1 day 3 days 7 days comparative1.6 × 10⁵ 1.7 × 10⁵ 1.6 × 10⁵ 1.7 × 10⁵ sample  190 mg Ag/kg 1.6 × 10⁵1.2 × 10⁵ 1.0 × 10³ <10  760 mg Ag/kg 1.2 × 10⁵ 7.8 × 10⁴ 7.3 × 10³ <103800 mg Ag/kg 1.6 × 10⁵ 8.8 × 10⁴ 1.4 × 10³ <10

TABLE 9 Bacillus subtilis spores microbial count after respectiveincubation time silver content 0 minutes 1 day 3 days 7 days comparative1.3 × 10⁵ 1.2 × 10⁵ 1.2 × 10⁵ 1.3 × 10⁵ sample  190 mg Ag/kg 1.1 × 10⁵9.5 × 10⁴ 9.7 × 10⁴ 1.6 × 10 ⁴  760 mg Ag/kg 1.2 × 10⁵ 1.1 × 10⁵ 8.4 ×10⁴ 1.7 × 10 ⁴ 3800 mg Ag/kg 1.3 × 10⁵ 8.8 × 10⁴ 7.7 × 10⁴ 1.1 × 10 ⁴

All results of the microbial count are afflicted with an error ofmeasurement of 10%.

The comparative sample was a paper without silver-containing fibres. Forall micro-organisms a dependency of the microbicidal effect on durationof treatment and concentration of the silver-load could be found. Thebacillus subtilis spores showed the highest resistance as expected. Butalso with these micro-organisms a decrease in microbial count could beachieved.

EXAMPLE 10

Fibres produced according to example 1 were spun in combination withcotton to stocking-yarn with a titre of Nm 68/1 and a silver content of1300 mg Ag/kg yarn. With this yarn a hose was knitted and examined onits bactericide effect (sample 31444083). The examination was carriedout according to SN195924. The test-organism was lactobacillus brevisDSM 20054. As test sample a not anti-microbially equipped cotton fabricwas used (Table 10). Five measurements were carried out on each sampleas well as the test sample. TABLE 10 Results of the examination of theanti-bacterial effect in a germ carrying experiment with Lactobacillusbrevis as examinated germ Ig KBE after X hours of contact 0- AE-valuessample 0 average 2 6 24 AE6 AE24 rating test 1 7,0 6,9 7,3 8,0 9,3 −1,1−2,4 test 2 6,8 7,2 8,0 9,3 −1,1 −2,4 test 3 7,0 7,3 8,0 9,3 −1,1 −2,4test 4 7,0 7,0 8,0 9,4 −1,1 −2,5 test 5 6,7 6,9 8,1 9,2 −1,2 −2,33144408.1 6,9 6,9 6,2 3,0 4,2 3,9 2,7 + 3144408.2 6,9 6,4 3,5 6,1 3,40,8 + 3144408.3 6,9 6,2 4,5 4,0 2,9 2,9 + 3144408.4 7,0 6,2 3,0 6,2 3,00,7 + 3144408.5 7,0 6,1 3,5 6,2 3,4 0,7 +KBE = number of colony-building units of test-bacteriaAE = antimicrobial effect

Evaluation-Cirteria:

The 24-hours-value of the growth-control (control, i. e.standard-fabric) has to be larger than the initial value by at least twoorders of magnitude (AE<−2).

An antimicrobial effect is given, if a KBE-value is at most 0.5 decadiclogarithms above the average value of the KBE at zero contact time, i.e. AE_(5.24)>−0.5.

The effect of an antimicrobial equipment is given, if for thetest-bacteria 4 of 5 single KBE-values of each contact time show anantimicrobial property. These requirements are met by the results ofsample number 3144408 (knitted hose).

1. A method for producing a cellulosic form that releases active agentsin an amount that reaches equilibrium in an aqueous solution, the methodcomprising: incorporating within a cellulosic solution a weakly linkedcation-active ion exchanger loaded with bactericide metal ions and/orwith ionic, pharmaceutic agents in such a manner, that a depot of saidagents is created within the fiber and that said depot releases theagents in an amount of the equilibration concentration upon applicationof these fibers or foils in aqueous solutions.
 2. The method accordingto claim 1, wherein the weakly linked, cation-active ion exchanger is apoly-acrylate.
 3. The method according to claim 1, wherein the metalions comprise silver ions.
 4. The method according to claim 3, furthercomprising additional bactericidally active metal ions, includingcopper-, mercury-, zirconia- or zinc ions.
 5. The method according toclaim 1, wherein the ionic pharmaceutic agents are anion-active agents,including benzoic acid or sorbic acid.
 6. The method according to claim1, wherein the concentration of the active agents is in the range of0.005 g to 100 g per kg of the cellulosic form.
 7. The method accordingto claim 1, wherein the cellulosic form is a fibre, which has beenloaded with active agents, blended with textile fibers and processedinto area-measured material.
 8. The method according to claim 7, whereinthe textile fibers are selected from the group comprising cotton, wool,polyester-fibers, polyamide-fibers, polyacryl-fibers,polypropylene-fibers or cellulosic synthetic fiber.
 9. The methodaccording to claim 2, wherein the cellulosic form further comprisescation-active and/or anion-active ion-exchangers.
 10. A cellulosic form,characterised in that said form contains weakly linked cation-active ionexchangers, wherein the ion exchanger is loaded with bactericidal metalions and/or ionic pharmaceutic agents and that said form releases inaqueous solutions the metal ions and/or agents at a concentrationcorresponding to the current equilibration concentration.
 11. Thecellulosic form according to claim 10, characterised in that the metalions are at least in part silver ions.
 12. The cellulosic form accordingto claim 11, wherein the form is a fiber and is intermixed with acompatible material to form a mixture.
 13. The cellulosic form accordingto claim 12, wherein the mixture is used to form a paper, a sausagecasing or a non-woven fabric.
 14. A lyocell-type cellulosic formcontaining an active agent that is released from the material relativeto the concentration of the active agent in an aqueous solutioncontacting the material, the material comprising: a mixture of acellulosic material, active agent and a polymeric resin withcross-linkers in an amount from about 0.1 to 2.0 weight % of the resinand wherein the amount of active agent in the material is proportionalto the amount of polymeric resin in the mixture.
 15. The lyocell-typecellulosic form according to claim 14, wherein the polymeric resin ispolyacrylate and the active agent is silver ions.
 16. The lyocell-typecellulosic form according to claim 15, wherein the form is a fiber forproducing a woven or non-woven fabric.
 17. A method of producing alyocell-type cellulosic form containing an active agent that is releasedfrom the material relative to the concentration in an aqueous solutioncontacting the material, the method comprising: providing a cellulosicmaterial comprising cellulose homogenized in N-methylmorpholine-N-oxidemonohydrate; mixing in a polyacrylate polymer in a form that isintermixed with the cellulosic material; forming cellulosic/polymerfibres; removing residual N-methylmorpholine-N-oxide monohydrate fromthe cellulosic/polymer fibres; contacting the cellulosic/polymer fibersto a solution of silver nitrate for a sufficient time to load thecellulosic/polymer fibers with silver ions in an amount proportional tothe amount of polyacrylate polymer introduced into the cellulosicmaterial.